Snake-Arm Robot Spherical Joints for Confined-Space Stiffness
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Solution Overview
Problem
Existing snake-arm robots face limitations in payload capacity, stiffness, and elastic instability due to the line of action of compressive forces acting on joints, which restrict their access to smaller and more confined environments.
Innovation Solution
The design of a snake-arm robot with joints featuring convex contact portions that maintain a line of action coincident with the point of contact between contact surfaces, allowing for reduced elastic instability, increased payload capacity, and enhanced stiffness, while minimizing complexity and enabling access to smaller spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional snake-arm robot joints are used, then the robot can access confined spaces, but the payload capacity and stiffness are limited due to elastic instability
Solution Approach 1:
The patent employs spherical contact portions at the joints instead of traditional cylindrical or planar contacts. This spherical geometry allows the contact points to naturally align with the line of action of compressive forces during articulation, reducing elastic instability and improving payload capacity while maintaining the ability to navigate confined spaces
2Adaptability or versatility
If traditional snake-arm robot joints are used, then the robot can access confined spaces, but the stiffness is reduced due to elastic instability
Solution Approach 1:
The spherical contact portions create a geometric configuration where the contact point between articulating links always lies on the line of action of compressive forces. This eliminates moment arms that would otherwise cause elastic buckling, significantly improving stiffness while preserving the robot's ability to bend and access confined spaces
3Volume of moving object
If the robot is miniaturized to access smaller spaces, then access to confined environments is improved, but elastic instability increases
Solution Approach 1:
The spherical contact geometry provides a scale-independent solution to elastic instability. By ensuring that contact points align with force lines of action through curved spherical surfaces, the design reduces buckling tendencies regardless of the robot's size, enabling safe miniaturization for access to smaller confined spaces
Data Source
AI summary
A snake-arm robot assembly may include a first link and a second link with a joint formed therebetween including first and second contact portions in rolling contact with one another to allow the first and second links to pivot with respect to one another. The first and second contact portions are configured to contact one another at first and second contact points corresponding to a first orientation and third and fourth contact points corresponding to a second orientation. The joint may be configured such that a line of action of a net force acting on the joint is incident with a first reference line extending between the first and second contact points with the links in the first orientation, and the line of action is incident with a second reference line extending between the third and fourth contact points when the links are in the second orientation.